This invention relates to a stencil for preparing a printing master and, more specifically, to a stencil having a porous substrate on which a thermoplastic resin film is bonded with an adhesive.
A stencil printer capable of performing a series of printing operations including the feeding of a stencil to a master forming section, the cutting of the stencil with a thermal head to form a printing master, the mounting of the master on a drum, the printing of a paper with an ink through the master, and the discharging of the used master is now widely used in various facilities, such as schools and offices, for producing various kinds of printings, because of easiness in handling, low costs and compactness thereof.
The stencil is generally composed of a porous substrate such as a thin paper, a thermoplastic resin film laminated on the substrate with an adhesive and, optionally, an anti-stick layer for preventing the fuse bonding of the thermoplastic film with a thermal head and the blocking of stacked stencils.
The problem with known stencil printers is that thin lines of the printed pattern are apt to be broken and white blanks are often present in the printed solid pattern. Such printing defects are more significant with an increase of the number of the printing masters produced. While extensive studies have been made on both printer parts and stencils, the above problem has not yet been completely solved.